1. Related Field
The present invention relates to a brewer unit for a hot beverage dispensing machine and including an upper cylinder for receiving and containing hot water and a brewing material and having an open lower end, a coaxial lower cylinder having an open upper end, a filter unit mounted over the upper end of said lower cylinder preventing passage of the brewing material therethrough, a reciprocal piston fitted in the lower cylinder, a rotary drive shaft connected to the piston by a crank and a piston rod to reciprocate the piston, a first mechanism for lifting the upper cylinder from the filter unit, a scraper unit, and a second mechanism for moving the scraper unit across the filter unit to remove spent brewing material therefrom, said two mechanisms being driven from the drive shaft.
2. Description of Related Art
EP 0 473 289 A1 discloses a brewer unit for a hot drinks dispensing machine includes a brewing cylinder having a pressure-applying piston and into which tea leaf or ground coffee and hot water are introduced, the base of the cylinder being a filter screen. The base and cylinder walls are movable relative to each other between a position of sealing engagement and a spaced-apart position and a wiper arm is positioned externally of the cylinder adjacent to the filter. In use, the piston applies pressure to the cylinder contents while the base and cylinder are in sealing engagement, whereby brewed beverage is forced through the filter, and the cylinder and base then move apart to allow the wiper arm to traverse the filter in the space formed, to remove spent tea leaf or coffee grounds therefrom in readiness for the next brewing cycle.
U.S. Pat. No. 4,903,586 discloses a beverage brewing machine which has upper and lower brewing chambers which are moveable relative to each other so as to clamp a strip-shaped filter there between during the brewing process and the chambers can be separated so as to allow the filter strip to be removed from the brewing chamber and the beverage residual wiped therefrom after which the filter strip is returned to the brewing chambers which are then resealed for the next cycle. A hold down grid engages the top surface of the filter to hold it down as a piston moves in the lower chamber upwardly to force air through the filter to agitate the beverage. When the piston reaches top dead center, the hold down grid is lifted. When the piston passes the opening the brewed coffee is poured. A loose connection is provided between the connecting rod for the piston and the driving crank arm so that the piston remains longer at the top and bottom of its stroke.
U.S. Pat. No. 5,349,897 discloses an apparatus for brewing coffee, tea or other beverages that has upper and lower chambers that move relative to each other. When the upper and lower chambers are joined, coffee and water are supplied to the upper brewing chamber which passes through a filter mounted on the top of the lower brewing chamber into the lower brewing chamber and the coffee grounds remain on the filter. A piston in the lower chamber forces air through the liquid to agitate it and sucks it through the filter into the lower chamber. The coffee flows from the lower chamber and then a single push rod separates the upper and lower chambers. A wiper blade then removes the coffee grounds from the filter while the chambers are separated, after which the push rod reseals the upper and lower chambers together for the next brewing cycle.